Friday, June 25, 2010

Making It My Own: Part 3 - Air Cleaner and Tuning

As was the case with my exhaust system, making a decision on which high-performance air cleaner to go with was a painstakingly slow decision. I kept browsing the J&P Cycles catalog, trying to find an air cleaner kit that would achieve both good looks and performance.

Just about any aftermarket air cleaner delivers better performance than the stock airbox, so the main issues are looks and cost. Some air cleaner kits sell for as much as $500, which is way more than I wanted to spend. I narrowed the finalists down to Arlen Ness Big Sucker and Doherty Machine Power Pacc. Of those two kits, the Doherty is more expensive (if you go with the PowerVent crankcase breather option), but my online research revealed nothing but stellar reviews of the Power Pacc kit. The backing plate is an extremely solid and finely-machined piece of billet aluminum, and the PowerVents add a nice dash of bling to the engine.

The instructions that came with the Doherty air cleaner kit were almost an afterthought (you would think the company would put as much effort into the instruction sheet as they did with their product); however, the kit is very intuitive and easy to install nevertheless.

Unlike the Arlen Ness kit, the Doherty kit does not include an air cleaner cover, although a plain chrome one can be ordered for $124 (way too much, in my opinion, for a plain cover). A chrome cover is mostly for appearance, though, since the gloss black painted air filter element retainer can act as a cover, as long as you use the buttonhead bolt to plug the center hole. The bike actually has a 'lean and mean' look without a chrome cover. One concern is that the air filter element could be exposed to rain, which, if heavy enough, could affect how the bike runs. You can install the stock 'football' or 'ham can' cover over the Doherty filter, and this would protect the filter from getting hit directly with rain, while still allowing plenty of airflow.

With the Vance & Hines exhaust pipes, my modified CV carb and the Doherty Power Pacc air cleaner all installed, I was ready for the moment of truth as I got ready to start my bike. I feared I would have difficulty starting it since the carb's float bowl was dry, but I only had to crank the starter about 10 seconds before the engine started. It actually started quite easily and idled well. Another big concern was exhaust leaks, but the gaskets had sealed well. I revved the engine and enjoyed the deep rumble from the Vance & Hines pipes.

I took a quick ride around my neighborhood to warm the engine up before fine-tuning the idle mixture screw, and immediately I noticed some differences, both in the way my bike sounds and the way it runs. The new pipes are a lot quieter when I am on the bike riding it. I could hear the normal top-end noises from my engine; my clutch lever rattling at idle; and another rattle, possibly from my backrest or luggage rack. I can also hear my gears shifting a lot more loudly now. And, I can hear the open-element air cleaner sucking air into the engine.

After a warm-up ride, I followed CV Performance's instructions for tuning the idle mixture. Using just my fingers, I turned the EZ-Just mixture screw in until the engine's idle speed began to slow, then I began to turn it out again in quarter-turn increments. I also adjusted the idle speed by ear, since I don't have a tachometer. The bike has a very smooth throttle response now, and I can feel more low and mid-range acceleration. It goes from 0-to-50 mph very quickly, and seemingly with very little effort. I did notice, though, that I sacrified some top-end performance. I imagine that is mostly due to no longer having open pipes, although for some reason, my throttle feels like it does not twist as far as it used to. It could simply be my imagination, but I will have to check my cables again to confirm my throttle is fully opening. But the best thing is that the bike has much better drivability. It seems to warm up faster, and I no longer have that annoying tendency to stumble every time I give it slightly more throttle.

It does sneeze through the carb occasionally when I roll on the throttle after a full stop, but I have been opening the idle mixture screw a few more times, and the sneezing is happening less and less often. I think I am at or near the 'sweet spot' of adjustment, since after my last adjustment, I get hardly any popping on deceleration, and the bike seems to coast down smoothly when I let off the throttle in gear.

Overall, the bike seems a lot more refined, even if I did lose some brute, full-throttle power. I am also getting used to the sound of the new pipes, which have a deep Harley rumble, and a low growl when I accelerate harder, although I can't make a bridge underpass echo like I used to, lol. My girlfriend Anna, actually liked the louder pipes, even though we can now talk to each other while riding. But, according to a guy I ride with sometimes, Tom Calci, who rides a Kawasaki, the new pipes are "still too loud" for his tastes. Just goes to show you can't please everyone when it comes to exhaust pipes, although most people like how the bike looks.

"She sure looks purty," Anna said in her southern drawl.

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